New Method for Synthesis of Various Types of Substituted 2(5H)-Furanones

A combination of the reaction of dianions of (phenylthio) acetic acid and its homologs with epoxides, the conjugate addition reaction of 3-phenylthio-2-(5H)-furanones with carbanion species, and the α-alkylation reaction of α-phenylthio-γ-butyrolactones is shown to provide a general method for the synthesis of a variety of substituted α-phenylthio-γ-butyrolactones. Oxidation of these α-phenylthiolactones to the corresponding sulfoxides, followed by pyrolysis furnishes all the types of substituted (3-, 4-, and 5-mono-; 3,4-, 3,5- 4,5-, and 5,5-di-; 3,4,5-tri-) 2(5H)-furanones in good overall yields.